Neil J J, Shiran S I, McKinstry R C, Schefft G L, Snyder A Z, Almli C R, Akbudak E, Aronovitz J A, Miller J P, Lee B C, Conturo T E
Div of Pediatric Neurology, St Louis Children's Hospital, MO 63110, USA.
Radiology. 1998 Oct;209(1):57-66. doi: 10.1148/radiology.209.1.9769812.
To establish quantitative standards for the directionally averaged water apparent diffusion coefficient (D) and quantitative diffusion anisotropy (A sigma) of normal brains in newborns by using diffusion tensor magnetic resonance (MR) imaging.
Diffusion tensor MR imaging was performed during the first 36 hours of life in 22 newborns (gestational age range, 31-41 weeks). Values of D and A sigma were measured in regions of interest chosen in the cortical gray matter, centrum semiovale, caudate nuclei, lentiform nuclei, thalami, internal capsules, and cerebellar hemispheres.
The D values in the gray and white matter in newborns are considerably higher than those in adults. There is a striking correlation between gestational age and D, with D decreasing as gestational age increases. The A sigma values in the white matter in newborns are lower than those in adults. Values of A sigma show statistically significant correlations with gestational age only in the white matter of the centrum semiovale, in which A sigma values increase sharply near term.
The D values primarily reflect overall brain water content. The A sigma values are more sensitive to tissue microstructure (e.g., white matter packing and myelination). The D and A sigma images reveal information and not apparent on T1- and T2-weighted images.
通过使用扩散张量磁共振成像，建立新生儿正常脑的定向平均水表观扩散系数（D）和定量扩散各向异性（A sigma）的定量标准。
对22例新生儿（胎龄范围31 - 41周）在出生后36小时内进行扩散张量磁共振成像。在皮质灰质、半卵圆中心、尾状核、豆状核、丘脑、内囊和小脑半球中选择感兴趣区域测量D值和A sigma值。
新生儿灰质和白质中的D值明显高于成年人。胎龄与D之间存在显著相关性，随着胎龄增加D值降低。新生儿白质中的A sigma值低于成年人。仅在半卵圆中心白质中，A sigma值与胎龄存在统计学显著相关性，其中A sigma值在足月时急剧增加。
D值主要反映脑总体含水量。A sigma值对组织微观结构（如白质堆积和髓鞘形成）更敏感。D和A sigma图像揭示了在T1加权和T2加权图像上不明显的信息。
